A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying goods or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity, and tradition.
Deep and dark, the Mud Hole is the Hudson River's channel from a time when the oceans were much lower. Today it collects all the silt and sediment that the river carries out to the sea, making it a very fertile fishing ground, frequented by pelagic fishes and sharks. The contour shown on the chart is not any particular depth, but do give an idea of the location.